A River in the Sky is by Elizabeth Peters. The nineteenth book in the Amelia Peabody series. This book is set in 1910, pre-WWI. Ramses is in Palestine assisting on a dig and finds himself caught up in a German espionage plot. The War Office sends the Emerson's to Jerusalem to stop a possible German spy from antagonizing the locals by excavating on the Temple Mount. The two plots are, of course, connected. Fans of this series will enjoy this book.
Ratings: 9th grade - 8 out of 10 - P (profanity) - AC (some mature thematic content).